Chess is a two-player strategy board game played on a chess board, a checkered game board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide in homes, parks, clubs, online, by correspondence, and in tournaments.
Each player begins the game with 16 pieces: one King, one Queen, two Rooks, two Knights, two Bishops, and eight Pawns. One player plays with “white” pieces, while the other player plays with “black” pieces, although the pieces may not actually be black and white in color. The two different sets of pieces of each player are always in contrasting colors. Each of the six piece types moves differently. Pieces are used to attack and capture the opponent's pieces, with the objective to “checkmate” the opponent's King by placing it under an inescapable threat of capture. In addition to checkmate, the game can be won by the voluntary resignation of the opponent, which typically occurs when too much material is lost, or if checkmate appears unavoidable. A game may also be won when one player runs out of time as measured by a chess clock. It is also possible for a game to result in a draw, or stalemate, where neither player wins.
The chess pieces themselves are made of many different materials, including, but not limited to plastic, wood, ceramic, ivory, bone, stone, glass, marble, and metal (including precious metals). Common woods used to make chess pieces include Boxwood, Ebony, Rosewood, Sandalwood, Sheesham, Maple, Palm, Cedar, African padauk, and Olive wood. Virtually any wood can be used to make chess pieces, although some are better than others due to weighting and cracking concerns discussed further below. Ebony and Rosewood are among the most common woods used for high end chess sets. They are very expensive woods. Thus, the sets made out of these woods are very desirable.
Chess sets made of metal are mainly made of alloys of zinc, tin, copper and aluminum. Pewter, another alloy of tin (about 85% to 95%) and copper (about 1% to 5%) are also used to make good metal chess sets. In appearance, pewter has the appearance of silver and provides a high profile look. Apart from the mentioned metals, alloys like bronze (copper and tin) and brass (copper and zinc) are also used to make metal chess sets. Marble chess pieces are made of either artificial marble or pure marble. The making of stone chess sets is done in the same process as marble. Chess sets are also made of deer antler, camel bone and ivory. The United States banned the import of ivory in 1989, and other countries have followed suit. Ivory chess sets are usually both rare and valuable.
During the first half of the 19th century, a surge in the global popularity of chess brought about the demand for a uniform model of chess pieces. While the variety and styles of chess pieces that were in use at the time were extensive, they were decorative in nature and considered unsuitable for play. Chess has historically been enjoyed by the wealthy, a fact that is reflected in the artistic designs of chess sets that dominated the marketplace. While aesthetically beautiful, the chess pieces of the period were not very practical. The chess pieces were expensive to produce, cumbersome to use, prone to tipping over and had such ornate details that they were unable to withstand the wear and tear of regular use. However, the greatest disadvantage of these chess sets was the lack of uniformity of the pieces within a chess set—a player's unfamiliarity with a particular chess set could affect the outcome of the game and were prone to tipping over due to poor stability. Complaints such as these led to the search for a standard design of chess pieces. On Sep. 1, 1849, An Ornamental Design for a Set of Chess-Men (No. 58607) was registered by Mr. Nathaniel Cook under the British Ornamental Designs Act of 1842.
Our research has lead us to conclude that the basis for this new design of chess pieces was the Northern Upright Chess Set, © 1840, by Lord John Hay. Complaints about the contemporary designs of chess pieces were well established in chess circles. By starting with an extremely popular yet highly artistic chess set, Mr. Cook was able to focus his energies solely on correcting those deficiencies. The ornate features that were most susceptible to damage were removed, resulting in a chess set that was durable and less expensive to produce. The diameter of the bases was widened for increased stability and the chess pieces were weighted with lead for ballast. Before the commercial launch of these new chess pieces, Mr. Cook convinced Howard Staunton to lend his prestigious name to the new design. Mr. Staunton was England's most celebrated chess personality and the unofficial World Champion. The Staunton Pattern Chessmen, as they were officially known, became commercially available on Sep. 29, 1849 and quickly became the world standard of chess pieces. Their lower production cost brought chess to the masses and did much to popularize the game. Its clean, simple design has never been equaled—the Staunton pattern chess set looks as modern today as it did upon its introduction more than 150 years ago. As a result, the Staunton style chessmen is the standard used in tournament play today, and is most common in club/casual play as well.
Chess designs are often identified using the Camaratta codex (named for the present inventor) by the appearance of the Knight, and enjoy interesting names, including that of Nathaniel Cook himself, as well as many famous players, (“Cook”, “Morphy”, “Harrwitz”, “Paulsen”, “Anderssen”, “Anderssen drop jaw”, “Steinitz”, “Tarrasch”, “Zukertort”, “Lasker”, “Pre-Hartston”, “Hartston”, “Marshall”, “Nimzovich”, “Broadbent” and “Lessing”.) More recent sets are known by names of cities where they were produced (e.g., “Zagreb”, “Reykjavik”), in honor of modern champions (“Capablanca”, “Marshall”, “Fischer”) or to commemorate certain important tournaments (“Fischer-Spassky”, “Sinquefield Cup”).
Frank A. Camaratta, Jr., the present inventor, is an internationally recognized expert in antique Staunton and other playing sets. He has been a serious collector and researcher of antique playing chess sets, their design and history, since 1986. This research, which began in 1989, was centered on Jaques and other Staunton chessmen and quickly expanded into Pre-Staunton playing sets. In 1990, he founded The House of Staunton, offering the finest manufactured and antique chess equipment in the Staunton pattern. He has also written several articles and given numerous lectures on the subject of Staunton chessmen. His research includes categorizing the various Staunton designs and their evolution starting with their introduction in September of 1849. He is widely known and respected as a designer and manufacturer of chessmen. Mr. Camaratta's chess pieces, available from The House of Staunton, are well known and used in some of the most prestigious chess tournaments in the world, such as the U.S. Chess Championship, and the Sinquefield Cup (a tournament that usually boasts the highest rated players in the world, including World Champion Magnus Carlsen.)
A long-felt problem associated with the manufacture of chessmen has to do with weighting them, and with problems that weighting causes. Chess players like to play with “heavy” pieces. It is common, then, for both plastic and wood pieces to be weighted. Wooden chessmen crack because manufacturers use lead, steel, plaster of Paris, and concrete in solid form to add ballast to the chessmen to improve their stability and tactile qualities during play. Unweighted chessmen almost never crack, regardless of the size of the piece or the species of wood used. It has very little to do with how well the wood is seasoned. Poorly seasoned wooden chessmen will usually tend to warp or bend rather than crack. The cracks almost always emanate from the base outward, then upward as the crack begins to open.
The actual mechanism behind the tendency of weighted wooden chessmen to crack is shrinkage due to loss of moisture in dry environments combined with the presence of the solid weighting material which hinders this contraction. This loss of moisture can be caused by climatic and geographic factors as well as the type of heat used during the winter months. The mechanics of the problem can be explained by looking at what happens when a chessman loses moisture. To add weight to a chess piece, a hole is bored into the base and a solid slug of metal, usually lead, is inserted into the base. There are two methods by which this can be accomplished. First, molten lead can be poured into the cavity. This is the most common method employed today by manufacturers of chessmen in India. It has the major disadvantage of scorching the wood locally and drastically changing its material properties. This method can also significantly embrittle the wood. Second, the weighting media can be cast or machined to shape outside the wooden cavity, then glued or screwed into place. This would be a good solution if the manufacturing process used could control the tolerances in the wood and maintain a uniform “gap” between the wood and the weight. This has been marginally successful in preventing cracking.
When the wood loses moisture, it shrinks That means the diameter of the bore gets smaller. However, the weighting material, which is a solid cylindrical slug, does not shrink. So, the wood needs to “stretch” in order to fit around the weight. This induces hoop strains in the wood. The second mechanism which works in concert with the “stretching” is the presence of small flaws which are dispersed throughout any piece of wood. Then, these flaws, which can't be seen with the naked eye, appear at the outer edge of the bore, and become potential crack initiation sites.
If the wood is reasonably compliant and has a low notch sensitivity, or if there is sufficient space between the lead weight and the inside edge of the bore, these induced hoop strains can be kept relatively low. Certain woods, like Rosewood (genus Dalbergi, a large species of small to medium-size trees) and its close relatives like Cocobolo and African Blackwood, are relatively compliant (they have a relatively shallow stress/strain curve), have good notch sensitivity, and can stretch without inducing hoop strains sufficient to exceed its modulus of rupture. Think of a rubber band or some such material. It can stretch with little effort. However, in certain very strong woods, like Ebony, which are very notch-sensitive, its strength and steep stress/strain curve work against it. It has very little “give”, so it takes high hoop strains to force the Ebony base to conform to the solid lead weight. If those strains exceed the modulus of rupture, of if they are sufficient to cause those minute flaws to grow into fatigue cracks over time, the wood will fail. Boxwood (actually Indian Whitewood), which is almost universally used for the light colored chessmen, is relatively forgiving in this respect, but not quite as good as woods in the Rosewood family. In all cases, however, the praxis of pouring molten lead into the base cavity of the chessmen exacerbates this problem by significantly altering the mechanical properties of the wood, making it more brittle, and opening the minute fissures (flaws) normally present.
Another problem with weighting chess pieces stems from the fact that black pieces in a chess set are traditionally made of a wood that is denser than that used for the white pieces. For example, Ebony has a higher density than Boxwood. This means that, if a manufacturer uses the same unitary weight (e.g., a lead slug) to weight each piece, each black piece will likely weigh more than its white counterpart. This is not desired and another problem to be solved by the present invention.
Since 1972, when Bobby Fischer defeated Boris Spassky to become the World Chess Champion, the game of chess has enjoyed a surge in popularity that continues even today. As computer technology and the Internet have evolved, chess players and aficionados are now able to watch top Grand Masters play in international tournaments via the Internet. Sophisticated sensory chess boards are able to sense the location of each piece on the board, transmit these locations to a computer, and then broadcast the game, move by move, over the Internet. These high-level games are usually accompanied by live expert commentary by Grand Masters and International Masters.
One such manufacturer of a sensory chess board is DGT Projects, B.V., of Enschede, Netherlands. This company's products, known as “DGT Boards” are commonly used in many top level chess tournaments. In 2001, U.S. Pat. No. 6,168,158 (Bulsink) issued for an invention entitled, “Device for Detecting Playing Pieces on a Board,” incorporated herein in its entirety. The patent was assigned to DGT Projects, B.V. The patented invention uses chess pieces which include a resonance coil (sensor) embedded in each piece, and a board having a plurality of transmit and receive resonance coils embedded in the board which, together with an electronic circuit and software, are able to detect the position and identity of each piece on the board, and display it on a computer monitor. That is, the DGT Board and system, described in the patent, is able to correctly identify each piece, white and black, on each of the 64 squares on a chess board.
A problem with the DGT technology is that it has heretofore been thought impossible to weight the DGT chess pieces in such a way that does not interfere with the sensor/coil communication between the pieces and the coils embedded in the board. The traditional weighting material, lead, is a metal, and eddy currents on the surface of the lead weighting element create an electromagnetic field that interferes with the transmission of the signals between piece and board. It is not obvious that these pieces can be weighted with a metal. After all, Faraday's law would seem to suggest to an electrical engineer and chess piece designer alike that metal weights in the base of a “sensory” chess piece would induce current and generate electromagnetic fields that would interfere with communication between the sensor and board. As a result, chess pieces that are compatible with the DGT sensory chess board are notoriously light in weight, as shown in the table below:
Black KingWhite KingSetChess PiecesWeightWeightWeightDGT Classic Chess Pieces1.4 oz.1.3 oz.23.6 oz.DGT Ebony Chess Pieces1.6 oz.1.2 oz.24.8 oz.
By comparison, a traditional weighted wood chess set, such as the Frank Camaratta Signature Series Luxury Chess Set, with a 4.4″ King, and two extra Queens, made of Boxwood and Ebony and distributed by the House of Staunton, with only the Ebony pieces weighted by the method of the present invention, weighs 86 ounces (not including the extra Queens). Moreover, the House of Staunton Imperial Set, with a 3.5″ King, and two extra Queens, which is DGT-Enabled, meaning that each piece includes an electronic sensor (coil) that can communicate with a DGT Sensory Chess Board, where each piece is weighted according to the method of the present invention, weighs 54 ounces (again, not including the extra Queens). The weight of the black King in this DGT-Enabled set is 3.7 ounces, and the white King is 3.6 ounces, whereas the heaviest King heretofore available for this set from DGT Projects is 1.6 ounces.
In summary, then, wooden Staunton Style chessmen have been made and used for at least 165 years, and other styles of wooden chessmen have been known and used for long before this. The problem of cracking wooden chess pieces has been well-known and ever-present for as long as wood chess pieces have been made, and yet no one, before now, has solved the problem of weighting wood chess pieces in such a way as to prevent cracking. Moreover, it has always been known that the species of wood traditionally used to make black chess pieces is traditionally more dense than wood used to make white pieces, and that white pieces are usually lighter in weight than black pieces in any given set. Thus, a long-felt need has existed for a method of weighting chess pieces that prevents cracking of the pieces, does not interfere with the electronics in sensory type chess boards, and equalizes the weights of black pieces versus white pieces in any given set. A need has obviously also existed for the pieces produced by this method.